Pistacia vera L. as natural source against antimicrobial and antiviral resistance

Increased global research is focused on the development of novel therapeutics to combat antimicrobial and antiviral resistance. Pistachio nuts represent a good source of protein, fiber, monounsaturated fatty acids, minerals, vitamins, and phytochemicals (carotenoids, phenolic acids, flavonoids and anthocyanins). The phytochemicals found in pistachios are structurally diverse compounds with antimicrobial and antiviral potential, demonstrated as individual compounds, extracts and complexed into nanoparticles. Synergistic effects have also been reported in combination with existing drugs. Here we report an overview of the antimicrobial and antiviral potential of pistachio nuts: studies show that Gram-positive bacterial strains, such as Staphylococcus aureus, are the most susceptible amongst bacteria, whereas antiviral effect has been reported against herpes simplex virus 1 (HSV-1). Amongst the known pistachio compounds, zeaxanthin has been shown to affect both HSV-1 attachment penetration of human cells and viral DNA synthesis. These data suggest that pistachio extracts and derivatives could be used for the topical treatment of S. aureus skin infections and ocular herpes infections.


Introduction
Tackling antimicrobial resistance (AMR), considered a threat to global human health, is a key research priority.The term 'antimicrobial' includes antibiotic, antiprotozoal, antiviral and antifungal medicines.AMR causes an estimated death of at least 1.27 million people worldwide and was associated with nearly 5 million deaths in 2019, according to a recent report released in The Lancet (Murray et al., 2022).In the U.S., more than 2.8 million antimicrobial-resistant infections occur each year, resulting in the death of more than 35,000 people (CDC, 2019).The estimated national cost in the U.S. to treat infections caused by multidrug-resistant pathogens frequently found in hospital environments can be substantial, leading to more than $4.6 billion annually.Dedicated prevention and infection control efforts can reduce the impact of antimicrobial-resistant infections, lowering deaths by an average of 18% (and by nearly 30% in hospitals in the U.S. in 2019).However, the COVID-19 pandemic has harmed recent AMR prevention and control.Therefore, the United Nations and the World Health Organization are leading initiatives to raise awareness of the problem and deliver

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Zengfeng Zhang, Shanghai Jiao Tong University, China Mandalari et al. 10.3389/fmicb.2024.1396514Frontiers in Microbiology 02 frontiersin.orgsolutions to protect our ability to fight infectious diseases globally.Therefore, the discovery of novel therapeutics with antimicrobial and antiviral effects, to be used either alone or in combination with existing drugs, is warranted.
It is well known that plant extracts represent an important source of bioactive compounds, mainly secondary metabolites, which could be used for their antimicrobial and antiviral potential.Tree nuts are known to contain an array of phytochemicals with potential health benefits (Gervasi et al., 2021).However, the phytochemical content of tree nuts can vary considerably, and depends on nut species, genotype, pre-and post-harvest conditions, and storage conditions (Bolling et al., 2011).Additionally, processing approaches such as roasting, may affect tree nut phytochemicals.For example, the total phenol content and the ferric-reducing antioxidant power (FRAP) value both decreased in almond skins after roasting, although the flavonoids concentration was not affected (Bolling et al., 2010a).The choice of solvents used for polyphenols and phytosterols extraction also significantly affects their quantification, and biological activity (Ghırardello et al., 2010).Qasimi et al. (2016) tested the effect of five different solvents (water, 80% methanol, 80% ethanol, acetone and chloroform) on the polyphenols and proanthocyanidin quantification as well as the biological potential [total phenolic (TPC), total flavonoid (TFC, antioxidant capacity using DPPH radical scavenging and ferric reducing antioxidant power (FRAP) activities] of medicinal alophytes: results showed that 80% methanol was the most effective solvent, followed by ethanol and water.Pistachio (Pistacia vera L.) nuts represent a good source of protein, fiber, monounsaturated fatty acids, minerals, and vitamins, as well as carotenoids, phenolic acids, flavonoids and anthocyanins (Mandalari et al., 2021).The phytochemical fraction in pistachios is known to contribute to their antimicrobial and antiviral effect and could help overcome AMR (Mandalari et al., 2021).
Here, we present an overview of the antimicrobial and antiviral potential of pistachio nuts.In addition, the evaluation of pistachio polyphenols, alone or in combination with existing drugs, is described in this review in an attempt to provide novel tools to combat AMR.
Current research shows the principal health-related properties of bioactive compounds found in pistachios including their antioxidant and cytoprotective effects, their effect on cell redox homeostasis, as well as their anti-inflammatory and anti-cancer effects, neuroprotective, anti-obesity and anti-diabetic effects (Maestri, 2023).Additionally, a growing body of research has documented antimicrobial and antiviral properties associated with numerous pistachio compounds, as reported in Table 1 (carotenoids, chlorophylls, gamma tocopherol, phytosterols and resveratrol) and Table 2 (flavonoids, isoflavones, anthocyanins and proanthocyanidins).Here, we discuss the antimicrobial and antiviral properties of each of these classes of compounds in more detail.

Carotenoids
Carotenoids are tetraterpene pigments which exhibit orange, yellow, red and purple colours.Amongst the carotenoids present in pistachio nuts, β-carotene at a concentration of 100 mg/mL showed the best antimicrobial activity against the bacterial species Klebsiella  2020)).However, no effect was shown against Pseudomonas aeruginosa.In addition, β -carotene has been found to induce an increase from 1.4 to 3.8 log units in the bactericidal activity of a bovine lactoperoxidase system, evaluated using Salmonella enteritidis (Hayashi et al., 2012).According to Mitra et al. (2021), the carotenoid pigment lutein was able to inhibit both the growth and the proliferation of several Gram-positive and Gram-negative bacteria, such as Enterococcus faecium, S. saprophyticus, S. aureus, E. coli, P. aeruginosa, K. pneumoniae, at concentrations varying from 8 to 256 μg/mL.The in vitro antiviral activity of lutein against the hepatitis B virus (HBV) has been reported by Pang et al. (2010).The antiviral functions of lutein have also been investigated in stable HBV-producing human hepatoblastoma HepG2 2.2.15 cells, where it efficiently suppressed the dose-dependent secretion of HBsAg and inhibited extracellular HBV DNA.We have recently reported that zeaxanthin, a dietary carotenoid that accumulates in the retina as a macular pigment, exhibits strong antiviral activity against herpes simplex virus 1 (HSV-1, CC50: 16.1 μM, EC50 4.08 μM, SI 3.96), affecting viral attachment and penetration as well as viral DNA synthesis (Pennisi et al., 2023).An overview of the use of carotenoids as therapeutic strategies against emerging viral diseases, such as COVID-19, has recently been published (Khalil et al., 2021).The inhibitory activity of two marine carotenoids blocking the entry of SARS-CoV-2 has also been reported (Yim et al., 2021).

Tocopherols
Tocopherols are a class of organic fat-soluble phenolic compounds, many of which have vitamin E activity.The antibacterial potential of gamma-tocopherol has been demonstrated in flower extracts of Damask rose (Rosa damascena Mill), which contained beta-carotene, alpha-tocopherol and phenolic compounds as well as

Chlorophylls
The susceptibility of Gram-positive and Gram-negative bacteria to photodynamic therapy using natural chlorophylls, the green photosynthetic pigments found in plants, has been widely investigated (Bertoloni et al., 1992;Merchat et al., 1996;Minnock et al., 1996).The use of derivatives of natural chlorophylls as agents for antimicrobial photodynamic therapy has recently been reviewed also in relation to their effect against bacterial biofilm, which is known to be highly resistant to antibiotic treatment (Suvorov et al., 2021).A chlorophyll derivative pheophorbide A (PheoA), a porphyrin compound similar to animal Protoporphyrin IX, has shown an antiviral activity against SARS-CoV-2, preventing infection of cultured monkey and human cells, without noticeable cytotoxicity (Jimenez-Aleman et al., 2021).

Phytosterols
Phytosterols are plant-based compounds similar to cholesterol.Using the microdilution method, the phytosterol campsterol displayed a weak antibacterial effect in vitro against S. aureus (ATCC 6538), Streptococcus mutans (ATCC 0046), E. coli (ATCC 10536), P. aeruginosa (ATCC 15442), and K. pneumoniae (ATCC 10031), with minimum inhibitory concentration (MIC) values of 1.280 mM (Freitas da Silva et al., 2023).Through computational analyses, it was proposed that β-sitosterol exhibited antibacterial activity against several bacterial Vibrio species and could be used in aquaculture, both as a nutritional supplement and also as a disease control agent to prevent and control fish diseases caused by bacterial infection (Ravi et al., 2020).Furthermore, β-sitosterol isolated from the leaves of the South American firespike plant (Odontonema strictum) has been found to be active against S. aureus, showing both a bacteriostatic and a bactericidal effect (Pierre Luhata and Usuki, 2021).Yusuf et al. (2018) have demonstrated the antibacterial and the antifungal activity of stigmasterol isolated from the stem bark of the African tree species Neocarya macrophylla (Yusuf et al., 2018).

Flavonoids
Flavonoids are polyphenolic secondary metabolites found in plants.Extensive scientific literature is available on the antimicrobial and antiviral properties of catechins and epicatechins (Taylor et al., 2005;Reygaert, 2014).For example, epicatechin-3-gallate, epigallocatechin, and epigallocatechin-3-gallate have been shown to have antimicrobial effects against a variety of bacteria, including S. aureus, methicillin-resistant S. aureus (MRSA) and E. coli (Reygaert, 2014).Taylor et al. (2005) demonstrated that low concentrations of epicatechin gallate can sensitize MRSA clinical isolates to levels of oxacillin which can be readily achieved in clinical practice.
Amongst the flavanones, luteolin has also shown antibacterial potential against S. aureus and L. monocytogenes in vitro, by impairment effect on the cell membrane and restraining biofilm formation of both strains (Qian et al., 2020).A literature review on the antiviral mechanism of luteolin has recently been published by Lu et al. (2023): luteolin effectively inhibited coronavirus replication (Alzaabi et al., 2022;Chen et al., 2022), influenza virus (Lee et al., 2016), enterovirus (Chen et al., 2008;Cao et al., 2016), rotavirus (Knipping et al., 2012), herpes virus (Lu et al., 2023), and respiratory syncytial virus (Wang et al., 2020).In particular, it prevented viral infection by improving the host's nonspecific immunity and antioxidation capacity, thus inhibiting several pathways related to viral infection, including MAPK, PI3K-AKT, TLR4/8, NF-κB, and Nrf-2/ hemeoxygenase-1.Furthermore, luteolin was able to regulate the expression of specific receptors and factors, interfering with viral replication and thus promoting the repair of damaged cells induced by proinflammatory factors (Lu et al., 2023).Hong et al. (2006) demonstrated in vitro the antibacterial potential of the isoflavone genistein against the Gram-positive S. aureus and Bacillus anthracis strains (Hong et al., 2006).Furthermore, an investigation on the mechanism of action of genistein indicated altered cell morphology (formation of filamentous cells) on bacterial cells, together with an inhibition of DNA and RNA synthesis as shortly as 15 min after addition to a bacterial culture.Protein synthesis inhibition was also detected (Ulanowska et al., 2006).Genistein has also been shown to possess antiviral activity against the herpes B virus, acting synergistically with existing antiviral drugs (LeCher et al., 2019).An effect of genistein as a general kinase inhibitor against an arenaviral haemorrhagic fever surrogate virus has also been demonstrated (Vela et al., 2010).
The antibacterial and antifungal effect of the isoflavone daidzein has been reported against S. aureus (both ATCC and clinical strains) by Lalouckova et al. (2021).Dietary daidzein was able to inhibit hepatitis C virus replication by decreasing microRNA-122 levels (He et al., 2021).

Anthocyanins
Anthocyanins are a group of red and blue pigments found in plants and along with catechins, form subgroups within the flavonoids.The antimicrobial activity of anthocyanins and catechins against the foodborne pathogens E. coli and Salmonella sp. has been reported, with MIC values between 10-400 mg/mL (Ma et al., 2019).Mechanistically, anthocyanins can act as an antibacterial by destroying the cell wall of foodborne pathogens: anthocyanins extracted from the Assegai tree (Curtisia dentata) were able to destroy the E. coli cell wall (Doughari et al., 2012), whereas in another study, anthocyanins extracted from lowbush wild blueberries were able to destroy the cell membranes of E. coli O157: H7, with consequent cytoplasmic leakage (Lacombe et al., 2013).Although anthocyanins are active against different bacterial strains, Gram-positive bacteria are usually more susceptible than Gram-negative bacteria (Cisowska et al., 2011).We have demonstrated the effect of an anthocyanin extract from the flowering plant Roselle (Hibiscus sabdariffa L.) containing cyanidin-3-O-sambubioside and delphinidin-3-O-sambubioside against S. aureus ATCC 6538 and against a food isolate of L. monocytogenes.The effect was bacteriostatic against S. aureus (MIC = 2.5 mg/mL) and bactericidal against L. monocytogenes (Minimal Bactericidal Concentration, MBC = 2.5 mg/mL) (El Majdoub et al., 2021).
These reports illustrate the extensive antimicrobial and antiviral effects of pistachio phytochemicals, isolated or within plant extracts, alone and combined with existing drugs.In terms of antibacterial activity, Gram-positive strains were usually more susceptible than Gram-negative bacteria, with a mostly bacteriostatic rather than bactericidal effect.Amongst the Gram-positive bacterial strains tested, ATCC and clinical isolates of S. aureus were more susceptible to the effect of bioactive compounds.S. aureus and MRSA are known to be responsible of various infections, including biofilm-associated diseases, ranging from skin, prostheses, catheters and other biomaterials infections to more serious systemic diseases, such as endocarditis, pneumonia, and osteomyelitis.Given the increased incidence of antibiotic resistant S. aureus infections, especially within hospital settings, the discovery of natural compounds effective against S. aureus produced biofilm is a promising area for further clinical research (Mandalari et al., 2023).

Antimicrobial effect of pistachios and mechanism of action
Table 3 reports the antimicrobial effect of pistachio extracts and essential oil.We have previously demonstrated that polyphenol-rich extracts of natural raw shelled and roasted salted pistachios were active in vitro against a range of Gram-positive bacteria, with a bactericidal effect against ATCC strains and food isolates of L. monocytogenes, S. aureus and MRSA (Bisignano et al., 2013a).Furthermore, we have phenotypically characterized clinical isolates of Staphylococcus spp.and tested these for their sensitivity against natural raw and roasted salted pistachios: both extracts were active against clinical isolates of Staphylococcus sp., as well as the S. aureus ATCC 6538P (La Camera et al., 2018).We have also demonstrated that polyphenol-rich extracts of natural raw shelled and roasted salted pistachios were effective against L. monocytogenes food isolate strains (MIC values between 0.25 and 2.0 mg/mL) and against L. monocytogenes ATCC 13932 (Gervasi et al., 2022).Furthermore, the oil fractions from natural and roasted pistachios were effective against L. monocytogenes ATCC 13932 and Enterococcus faecium DSZM 17050.Other authors have confirmed the effect of a methanolic extract of pistachios against staphylococcal infections (Gutiérrez-Morales et al., 2017).Pistacia vera L. oleoresin has been tested in combination with levofloxacin, demonstrating a protective effect against H. pylori infection in an in vivo model of Galleria mellonella (62 and 63% survival using oleoresin and levofloxacin, respectively) (Di Lodovico et al., 2019).Pistacia vera L. oleoresin was also effective against oral streptococci, such S. mutans, with a demonstrated antibiofilm activity (Magi et al., 2018).The essential oil from Pistacia vera L. hulls was bactericidal against a range of S. aureus strains and E. coli at a concentration of 7.11 mg/mL (Smeriglio et al., 2017).A fungicidal effect of pistachio essential oil was demonstrated against standard and clinical strains of Candida sp. at concentrations between 2.50 and 5.0 mg/mL, D-limonene and 3-Carene being the most active components (D' Arrigo et al., 2019).The inhibitory activity of pistachio hull essential oil has also recently been demonstrated against S. aureus, B. subtilis and Aspergillus flavus (Shahdadi et al., 2023).
A pistachio hull extract has been used as a reducing and stabilizing agent with antibacterial and antifungal effects within copper nanoparticles (Bakhshi et al., 2021).
Overall, these studies demonstrate that pistachios extract and essential oil, alone or in association with existing drugs, could be considered good candidates for the development of novel drug formulations.Their activity against Gram-positive bacterial strains, including S. aureus, could be exploited to identify novel therapeutics with topical use (i.e., to treat skin infections).
Although further studies are warranted to evaluate the mechanisms of action involved in the observed effect exerted by pistachio extracts, Figure 1 reports some proposed molecular bacterial targets, as reviewed by Álvarez-Martínez et al. (Álvarez-Martínez et al., 2020).Polyphenols can target the bacterial cell wall, causing morphological damage to the cells, or destroying the structural integrity of the cell wall and intracellular matrix (Din et al., 2013;Pojer et al., 2013).
The different cell wall structure between Gram-positive and Gram-negative bacteria could explain the higher susceptibility of Gram-positive strains to phytochemical antimicrobial activity, given that the outer membrane of Gram-negative bacteria acts as a permeability barrier, therefore reducing the uptake of the phenolic compounds (Naz et al., 2007).Polyphenols can cause leakage by increased permeability of the bacterial membrane and the cell wall (Lambert et al., 2001;Wang et al., 2017).Specifically, catechins can cause destruction of the Gram-positive bacterial membranes through interaction with lipids, which determine phase separations (Reygaert, 2014).Furthermore, epicatechin, tannic acid, epigallocatechin gallate, quercetin and kaempferol demonstrated significant β -lactamase inhibitory activity, also in synergy with antibiotics such as ciprofloxacin and rifampicin (Lin et al., 2008;Bernal et al., 2010;Mandal et al., 2017).Other possible targets could be represented by cell surface adhesion proteins, membrane-bound enzymes and cell wall polypeptides (Naz et al., 2007).A bioactive fraction from the tree species Duabanga grandiflora fruit has been shown to inhibit the penicillin-binding protein 2a in MRSA strains (Santiago et al., 2015).
Regulation of bacterial gene expression has been proposed as an alternative mechanism of action by phytochemicals, either through against E. faecalis, L. monocytogenes and S. aureus has been also related to its ability to target RNA-and DNA-related molecules (Murtaza et al., 2014).Naringenin was able to bind the DNA of S. aureus ATCC 6538, resulting in major metabolic changes (Wang et al., 2017).Furthermore, the effect of phytochemicals on biofilm formation has been reported: for example, we have shown a dose-dependent effect of phloretin on biofilm production of S. aureus (Mandalari et al., 2023) and a dosedependent effect of a white grape juice extract on biofilms formation of E. coli and Pseudomonas aeruginosa (Filocamo et al., 2015).Another antibacterial effect of phytochemicals is related to the alteration of the level of bacterial metabolites, proton and ion equilibrium and adenosine triphosphate (ATP) synthesis inhibition, which could determine cell death (Lin et al., 2005;Engels et al., 2011).Certain polyphenols, such as gallic or caffeic acid, could reduce cytochrome activity and, therefore, oxidative phosphorylation, thus inhibiting bacterial growth (Shetty and Wahlqvist, 2004;Kwon et al., 2007).
It is worth noting that the antibacterial effect of polyphenolic plant extracts is often the result of synergistic, indifferent, or antagonistic interactions among the individual compounds.For example, we have demonstrated that bergamot (Citrus bergamia) fractions and the pure phytochemical compounds, neohesperidin, hesperetin (aglycone), neoeriocitrin, eriodictyol (aglycone), naringin and naringenin (aglycone), were active against Gram-negative bacteria (E.coli, Pseudomonas putida, Salm.enterica) with MIC values in the range 200 to 800 μg/mL.However, pairwise combinations of eriodictyol, naringenin and hesperetin showed synergistic and indifferent interactions, dependent on the selected, tested organism (Mandalari et al., 2007).Moreover, isolated phytochemicals and extracts are being used in combination with traditional antibiotics to sensitize multidrug-resistant bacterial strains (Hatano et al., 2005;Betoni et al., 2006).We have demonstrated a synergistic and post-antibiotic effect of tobramycin in combination with tea tree (Melaleuca alternifolia) oil against S. aureus and E. coli (D' Arrigo et al., 2010).This strategy could represent a valuable tool to combat AMR more effectively.4).We have previously shown that natural raw pistachio extracts (NRRE) significantly reduced the expression of critical viral proteins, including ICP8 (infected cell polypeptide 8), UL42 (DNA polymerase processivity factor), and US11.This reduction was associated with a decrease in viral DNA synthesis, highlighting the extract's inhibitory effects on HSV-1 replication (Musarra-Pizzo et al., 2020).More recently, we have further investigated the mechanisms involved in the anti-HSV-1 effect exerted by pistachio extracts (Figure 3): NRRE and roasted unsalted (RURE) pistachio polyphenols-rich extracts blocked virus binding on the cell surface, impaired viral DNA synthesis, and prevented the accumulation of viral proteins (Pennisi et al., 2023).Indeed, by testing six compounds present in pistachio polyphenolic extracts (α, β, and δ tocopherol, β-carotene, luteolin, and zeaxanthin), we have demonstrated that zeaxanthin inhibited HSV-1 replication by affecting both viral internalization and replication.Furthermore, zeaxanthin directly interacted with HSV-1 viral particles, leading to a   3).The Gaziantep sample-unripe (PV-GU) extract also showed notable antiviral activity.On the other hand, some extracts displayed outstanding activity against RNA viruses, such as PV-GR (Gaziantep sample-ripe) and PV-GP (Gaziantep sampleprocessed).Chhoud et al. (2022) reported the anti-HSV-2 activity of extracts from Pistacia vera male floral buds: the aqueous and polysaccharide extracts from male flower buds exhibited a selectivity index (SI) of 29.12 and 20.25, respectively.The extracts showed virucidal activity against HSV-2, likely by altering the viral membrane or interacting with viral ligands, thus inhibiting their binding to receptors on target cells.Finally, pistachio extracts have shown activity against Coxsackie viruses (CV) B2, B3, B4, and B5.Specifically, two pistachio allergens, 2S albumin (Pis v 1) and 11S globulin (Pis v 2.0101), were found to inhibit these viruses (Taghizadeh et al., 2020).

Conclusion
Due to the increased rates of resistance to antibiotics and antivirals, scientific research is continuously developing to find novel  Frontiers in Microbiology 11 frontiersin.orgcost-effective alternatives to reduce hospitalization and mortality rates.Amongst natural compounds, the phytochemicals present in pistachio nuts have been shown to exhibit significant antibacterial and antiviral activity against resistant and non-resistant strains.Some findings suggest that the antimicrobial and antiviral effects of pistachio polyphenolic extracts are the result of a balance of the individual bioactive compounds which in combination exert the activity.The synergistic interaction of certain phytochemicals with selected antibiotics or antiviral drugs could be a useful tool to overcome resistance.Nevertheless, isolated compounds, such as zeaxanthin, exhibit strong antiviral activity against HSV-1, affecting viral attachment, penetration and viral DNA synthesis.While the mechanism of action of pistachio extracts has been partly elucidated, further studies are required to identify more bioactive compounds responsible for the observed effect.However, based on the existing evidence, the use of pistachio extracts and derivatives should be encouraged for the topical treatment of S. aureus skin infections and ocular herpetic infections.Existing challenges in the development of antimicrobials from natural products, including cytotoxicity, production of highly active standardized extracts with defined mechanism of action under GMP conditions, and identification of bioactive components taking into account possible interaction amongst the individual compounds, should also be considered, together potential sustainability issues related to pistachio cultivation.

Funding
The author(s) declare that financial support was received for the research, authorship, and/or publication of this article.The work has been funded by the American Pistachio Growers (APG, United States).

FIGURE 1
FIGURE 1Proposed bacterial molecular targets of bioactives in pistachios.

Figure 2
Figure2illustrates the effectiveness of bioactive natural compounds against viral families.The antiviral potential of pistachio polyphenolic extracts, particularly against herpes simplex virus type 1 (HSV-1), has been demonstrated (Table4).We have previously shown that natural raw pistachio extracts (NRRE) significantly reduced the expression of critical viral proteins, including ICP8 (infected cell polypeptide 8), UL42 (DNA polymerase processivity factor), and US11.This reduction was associated with a decrease in viral DNA synthesis, highlighting the extract's inhibitory effects on HSV-1 replication(Musarra-Pizzo et al., 2020).More recently, we have further investigated the mechanisms involved in the anti-HSV-1 effect exerted by pistachio extracts (Figure3): NRRE and roasted unsalted (RURE) pistachio polyphenols-rich extracts blocked virus binding on the cell surface, impaired viral DNA synthesis, and prevented the accumulation of viral proteins(Pennisi et al., 2023).Indeed, by testing six compounds present in pistachio polyphenolic extracts (α, β, and δ tocopherol, β-carotene, luteolin, and zeaxanthin), we have demonstrated that zeaxanthin inhibited HSV-1 replication by affecting both viral internalization and replication.Furthermore, zeaxanthin directly interacted with HSV-1 viral particles, leading to a

FIGURE 2
FIGURE 2Graphical representation of bioactive natural compounds against viral families.

TABLE 1
Antimicrobial and antiviral effects of pistachio carotenoids, chlorophylls, gamma tocopherol, phytosterols and resveratrol.

TABLE 2
Antimicrobial and antiviral effects of pistachio flavonoids, isoflavones, anthocyanins and proanthocyanidins.

TABLE 3
Antimicrobial effect of pistachio extracts and essential oil.

TABLE 4
Antiviral effect of pistachios extracts.